Safety lock for electric switch boxes and panel board covers



June 5, 1951 s. s. GRADY 2,555,331 4 SAFETY LOCK FOR ELECTRIC SWITCH BOXES AND PANEL BOARD COVERS Filed Oct. 5, 1949 INVENTOR STEPHEN aeRaDv A '5 ATTORNEY Patented June 5, 1951 UNITED STATES PATENT OFFICE SAFETY LOCK FOR ELECTRIC SWITCH BOXES AND PANEL BOARD COVERS AppIicationOctober 5, 1949, Serial No. 119,594

3 Claims.

This invention relates to safety locks for electric switch boxes and/or covers for panel boards.

Electric switches, mounted upon panel boards and the like have conventionally been covered either by panel board: covers or actually enclosed in switch boxes, particularly when used in the basement of apartment houses and the like, where they may be accessible to tenants and. unauthorized persons. When these switches are associated with high voltage lines,. the danger of injury by unauthorized persons is of course constantly prevalent. For this reason it hasbeen conventional to provide covers either for the panel boards or provide boxes enclosing the panel board and covers for the boxes. These covers are then locked by the authorized attendant so that they may not be manipulated by unauthorized per sons.

Still furthermore, to protect even the authorized persons from injury, it has become common practice to provide control means for shutting oif the current, that is, foropening the switch while the doors were closed. and to prevent opening of the doors or covers for the switch. boxes or panel boards until the current is shut on. or the switch opened.

Among the objects of the present invention it is aimed to provide an improved safety lock for anchoring the cover for the switch box or panel board when the switch is closed or the current established, and only permit the door to be opened after the switch has been opened or the current interrupted.

More specifically, the present improved safety lock is particularly adapted for so-called snap switches which are positively anchored. in closed or open position and will automatically assume either position due to the spring control thereof, and the safety means is characterized by a handle or control element movable on the outside of the switch box or cover for the panel board and having an actuator operatively connected thereto for actuating the switch into open or closed position and for cooperating with a projection to anchor the door or cover against opening when the switch is actuated into closed position and in turn to release the co-verfor opening when the switch is actuated into open position.

These and other features, capabilities and advantages of the present invention will appear from the subjoined detailed description of specific embodiments thereof illustrated in the accompanying drawings, in which Fig. 1 is a perspective of one embodiment of a switch box in switch closing position with the cover closed and the control means in cover anchoring position.

Fig. 2 is a section on the line 22 Of Fig. 1. Fig. 3 is a section on the line 33 of Fig. 2.

Fig. 4 is a section on the line 4-4 of Fig. 2. Fig. 5 is a detail of rotatable plate illustrated in Fig. 3.

Figs. 6 and '7 are fragmental front and side elevations of another embodiment.

According to the embodiment illustrated in Figs. 1, 2 and 3, there is illustrated a switch enclosing container I having a base 2, upper side wall 3, lower side wall 4 and. two lateral side walls 5 and 6.. To the outer free edge of the side wall 5 in the present instance there is pivotally connected the cover '1 having the flanges 8 to overlap the side walls 3, 4, 5 and 6-, asparticularly shown in Fig. l. The hinges for connecting the wall 5 to the cover 1 are not shown, but obviously may be conventional without departing from the general spirit of the invention.

The wall 6 in the present instance has secured at its inner end adjacent the base 2 a yieldable bar 9 having a protruding orificed portion I0 and projections Ii. The orificed portion [0 with its projections H extend through the opening [2 in the-cover i, see Figs. 1 and 2, with the projections l I- being tensed by the bar '9 to engage the outer face of the cover I and thereby to anchor the same in position. When the cover I is otherwise free to be opened, it is only necessar to engage the orificed portion 10- and press the bar 9 toward the side wall 6 so that its projections l i will clear the cover 1 and permit the same to be opened. As shown in Fig. 1., the orificed portion l0 when protruding through the cover I may have secured thereto a padlock I3 to lock the cover I in closed position relative to the container I Still furthermore, the handle 41 may be locked in ofi position to, prevent the switch from being closed by unauthorized persons when av padlock, such as the padlock l4, extends through the orificed portion [5 formed on the cover I with it hasp encircling the handle 41.

In addition to the yieldable bar 9, see particularly Fig. 3, the wall 6 also has secured thereto the flange or ledge 16 constituting an obstructing device, in the present instance disposed directly below the yieldable bar 9v and extending at right angles tothe wall 6, but adjacent to its free end, see Fig. 4.

In the present instance the box I is illustrated as equipped for two lines, each having. a pair of fuse, clips, the two fuse clips I! adjacent the wall 6 being shown in Fig. 2 while only one of the pair of clips, to wit, the clip I8 of the other set is shown in Fig. 4. Since the connections for each line are substantially identical it will suffice to describe only the line associated with the clips l'l. One of the clips I1 is connected to the binding post [9, which in turn is connected to one end of the line to be controlled by the present switch. The other clip I! is directly connected to the flexible contact plate which extends downwardly for engagement by the metal head 2! on the interposer 22, which metal head 2| in current establishing position engages the lower flexible contact plate 23 connected to the other binding post 24, which in turn is adapted to be connected to the other end of the line.

The interposer 22 is slidably mounted between the flexible or yieldable contact plates 29 and 23 and operatively connected to the arm 25 pivoted at 26 to the plate 2?. This arm 25 forms a toggle with the blade 28 pivoted at 29 to the plate 21, the upper end of which blade 28 is connected by the spring 30 constituting the first spring with the lower end of the arm 25. The spring 30 in contact making position or current establishing position is disposed above the pivot point 26 of the arm 25, and in current interrupting position is disposed below the pivot point 26 of the arm 25.

The upper end of the blade 28 in the present instance is provided with an opening or mouth 3i for receiving the lip or ledge 32 formed on the slide 33. The slide or slidable plate in the present instance has two openings 34 and 35 through which project the brackets 36 and 37 having the outwardly eXtending fingers 38, 38, and 39, 39, respectively, to engage the inner face of the slide plate 33, one bracket 35 for the opening 34, and the other bracket 3? for the opening 35 to guide the slide plate 33 in its movement up and down along the inside of the cover 1. Although the slide plate 33 ordinarily is heavy enough so that it will remain in descended position when the door is open in order to insure so locating the slide plate 33, the lower end thereof is connected by the spring 43 constituting the second spring to the abutment 4! on the inner r face of the cover I. For manually actuating the slide plate 33, the same is provided with an outwardly projecting ledge or flange 42 for engagement by the fingers 43 and 44 of the plate 45,

pivoted at 46 to the cover 7 between the slide plate 33 and the cover I. The pivot point 46 constitutes a pin which extends through the cover '9 and has secured on the outer face thereof the handle 41. This handle when moved into the position shown in Fig. 1 by rotating the plate will cause the lower arm 44 to engage the lower face of the ledge 42 and raise the slide plate 33 into the position shown in Fig. 3 against the tension of the spring 40. In turn, when the handle 4'! is swung to the right so that its pointer 48 points toward the notation off in Fig. 1, the arm 43 of the plate 45 will engage the ledge 42 and cause the slide plate 33 to descend.

When the arm 41 is swung into the position shown in Figs. 1 and 2 after the cover i has been closed due to the engagement of the flange 32, with the blade 28, it will actuate the blade 28 into the position shown in Fig. 2 where the spring 30 swings above the pivot point 26 and causes the contact block 2| to engage the two flexible contact plates 20 and 23 to permit the current to flow from the binding post IE! to the binding post 24.

The flange or obstructing device [6, on the side wall 6, is positioned so that when the slide plate 33 is in its lowermost position, it will clear the plate or first projection 49, see the dash and dot line position of the plate 49 in Fig. 3. On the other hand, when the cover I is closed and the handle 41 is then swung to the left, the position shown in Fig. 1, the plate 49 will be positioned adjacent to the flange l6 and behind the flange 16 so that the flange [6 will be interposed between the plate 49 and the cover I, and thus anchor the cover in closed position.

As aforesaid, in open position, the weight of the slide plate 33 is suflicient ordinarily to drop where it will swing the handle 41 into the position where its pointer 48 points toward the notation off on the cover 1. However, to insure retaining the slide plate 33 in its descended position when the cover is oil, the spring 40 is provided. Consequently, the cover "I cannot be closed until the switch is in open position, that is, where the blade 28 is swung downwardly with the spring 30 below the pivot 26.

Furthermore, the cover I cannot be moved into closed position since the end of the arm 49 in its raised position will not clear the flange Hi. It will only clear the flange l6 when the handle 41 is swung into the off position. Therefore, the cover 1 cannot be closed until after the arm 41 has been swung into the off position. In turn, when the cover 1 has once been closed and the arm 41 is in the on position, the flange IE will obstruct the plate 49 and prevent the cover I from opening. In other words, here too the cooperation of the flange l6 and plate 49 is relied upon to insure that the switch blade 28 has been swung into off position before the cover I can be opened.

Obviously the control for the slide plate 33 need not be mounted on the cover 1 without departing from the general spirit of the invention. As an instance, as shown in the embodiment illustrated in Figs. 6 and '7, a handle, such as the arm 50, may project from the side wall 5| and be operatively connected to the blade 28. In the embodiment illustrated in Figs. 6 and 7, the handle 50 is part of a bell crank 52 which extends through the box 53 being journalled in the opposing side walls, including the side wall 5|. The bell crank 52 has connected to it a rod 54, in the present instance, wrapped at one end around the portion 55 of the bell crank 52 and at its other end connected to the projection 56 formed on the blade 51. The blade 51 in this embodiment is illustrative of the blade 28 in the embodiment of Figs. 1, 2, 3 and 4. In this embodiment the circuit interrupting position, or off position, of the arm 50 would be the dotted line position shown in Fig. '7 and the on position would be the full line position of the arm 50 shown in Figs. 6 and 7. The cover 58 would be provided with a slidable plate, such as the slidable plate 33 shown in Fig. 3, having a flange I32 to cooperate with a flange IS in the "on position. The flange I32 is shown in dotted lines in engagement with the mouth l3| of the blade 51. The embodiment shown in Figs. 6 and '7, however, would dispense with the arm 41 and rotatable plate 45.

The flow of the current obviously enters by way of the binding post 24 and after passing through the switch passes to the load by way of the bind ing post l9.

After the cover 1 has been opened and the handle 41 is in the off position, if the switch blade 28 is in the on position, when an attempt is made to close the cover, the lip 59 constituting the second projection of the slide plate 33 will engage the lower bifurcation an of the mouth 3| of the switch blade 28. In turn, when the switch blade 28 is in the off position and. the handle 41 is in the on position, or any position except the extreme off position, the cover 1 cannot be closed due to the obstruction of the plate 49 by the ledge [5. Only when the switch blade 28 is in off position and the handle 41 is swung to the extreme ofi? position can the cover I be closed when the lip 32 will enter the mouth 3| of the switch blade 28, and the plate 49 clear the lip Hi.

In order to insulate all live parts of the switch, such as the binding post 24, contact plate 23, and the like, from the box or container I, there is provided the vulcanized fibre mat 6|, see Figs. 3 and 4, which has the upwardly extending flanges 62 and 63 interposed between the switch per se and the walls and 6, respectively, of the container l.

Furthermore, since the binding post 24 is con nected to the line, in order to protect the operator from accidental contact therewith, there is provided the vulcanized fibre skirt 64 hingedly con nected to the lip 65 which is secured to the extension 66 extending from the fixed metal plate 21. When it is desired to connect a conductor to the binding post 24, it is only necessary to lift the skirt 64 to gain working access to the same.

It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims.

Iclaim:

1. A device for insuring the registration of the switch blade of an electric switch and the actuating means for the switch blade, during the closing of the cover of a container for such electric switch characterized by a pivoted blade which has a first spring for actuating the blade beyond dead center either into, or for holding the blade in, circuit making or circuit breaking position, said device being characterized by a slide plate constituting the actuating means mounted on the inner face of the cover, means on said slide plate for operatively engaging the blade when in registration with one another and when the cover is closed, an obstructing device on the container, a first projection on said slide plate clearing said obstructing device when said slide plate and the blade are positioned in circuit breaking position, said first projection being disposed behind said obstructing device to anchor the cover in closed position when the slide plate and the blade are positioned in circuit making position, a second projection on said slide plate clearing the blade when the slide plate and the blade register with one another, said second projection engaging the outer edge of said blade to block the closing of the cover when the blade is in circuit making position and the slide plate is in circuit breaking position, a second spring yieldably urging the slide plate into, and maintaining the slide plate in, circuit breaking position when the cover is open and the slide plate is disengaged from the blade, the first spring of the blade opposing said second spring and maintaining the slide plate in circuit making position when the slide plate and the blade register with one another and the cover is closed, and a handle on the outside of the container operatively connected manually to actuate said slide plate.

2. The combination as set forth in claim 1 in which the handle is pivotally mounted on the outside of said cover and carried by said cover.

3. The combination as set forth in claim 1 characterized by a bell crank in said container, means fOr operatively connecting said bell crank to the blade, and in which the handle is fixed to the bell crank and extends outside of the container.

STEPHEN S. GRADY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,959,903 Cassidy May 22, 1934 2,163,230 Rowe June 20, 1939 

